Question 1

Stars larger than about 1.4 solar masses must lose mass in order to become white dwarfs.

Accepted Answer

A) True 
 B)False  True

Question 2

Red dwarf stars ____.

Accepted Answer

A)  never develop a hydrogen-fusion shell 
B)  create large amounts of carbon and oxygen 
C)  have much shorter lifetimes than Sun-like stars 
D)  never begin hydrogen fusion 
E)  become brown dwarfs after they exhaust their hydrogen core 
A)  never develop a hydrogen-fusion shell 
B)  create large amounts of carbon and oxygen 
C)  have much shorter lifetimes than Sun-like stars 
D)  never begin hydrogen fusion 
E)  become brown dwarfs after they exhaust their hydrogen core A

Question 3

White dwarfs are rare objects.

Accepted Answer

A) True 
 B)False  False

Question 4

A medium-mass star evolves into a red giant because ____.

Accepted Answer

A)  the core expands as new fusion products collect there 
B)  the surface of the star becomes cooler 
C)  energy from hydrogen shell burning and helium fusion forces the outer layer to expand 
D)  the surface of the star becomes hotter 
E)  increased stellar winds carry large amounts of material off of the surface of the star 
A)  the core expands as new fusion products collect there 
B)  the surface of the star becomes cooler 
C)  energy from hydrogen shell burning and helium fusion forces the outer layer to expand 
D)  the surface of the star becomes hotter 
E)  increased stellar winds carry large amounts of material off of the surface of the star

Question 5

The gravitational field around close binary stars is defined by _______________ lobes.

Accepted Answer

The answer of The gravitational field around close binary stars...

Question 6

What keeps red dwarfs from becoming giant stars?

Accepted Answer

Red dwarf interiors are highly convectiv

Question 7

A white dwarf stops collapsing and forms a stable structure due to forces arising from ____.

Accepted Answer

A)  rapid rotation 
B)  magnetic fields 
C)  gas pressure 
D)  neutron degeneracy 
E)  electron degeneracy 
A)  rapid rotation 
B)  magnetic fields 
C)  gas pressure 
D)  neutron degeneracy 
E)  electron degeneracy

Question 8

Almost all stars are in binary systems.

Accepted Answer

A) True 
 B)False

Question 9

A normal white dwarf is approximately the same size as ____.

Accepted Answer

A)  the Sun 
B)  Jupiter 
C)  Earth 
D)  a large asteroid 
E)  a house 
A)  the Sun 
B)  Jupiter 
C)  Earth 
D)  a large asteroid 
E)  a house

Question 10

All stars ignite helium fusion as part of the aging process.

Accepted Answer

A) True 
 B)False

Question 11

What is a planetary nebula?

Accepted Answer

A planetary nebula is a shell of gas tha

Question 12

Red dwarf stars (stars between 0.08 and 0.5 solar masses) evolve very differently than other stars as they age because ____.

Accepted Answer

A)  they are formed from pure hydrogen 
B)  they never reach the minimum temperature required to fuse carbon 
C)  they never form white dwarf as remnants 
D)  they are always part of a close binary system 
E)  their interiors are well mixed, through strong convection 
A)  they are formed from pure hydrogen 
B)  they never reach the minimum temperature required to fuse carbon 
C)  they never form white dwarf as remnants 
D)  they are always part of a close binary system 
E)  their interiors are well mixed, through strong convection

Question 13

Supernovae can trigger star formation.

Accepted Answer

A) True 
 B)False

Question 14

The Crab Nebula is the remnant of ____.

Accepted Answer

A)  the SN1987a supernova 
B)  a supernova which triggered a mass extinction on Earth 
C)  a supernova recorded by Chinese astronomers 
D)  a supernova which triggered the formation of the Sun 
E)  a supernova in the Large Magellanic cloud 
A)  the SN1987a supernova 
B)  a supernova which triggered a mass extinction on Earth 
C)  a supernova recorded by Chinese astronomers 
D)  a supernova which triggered the formation of the Sun 
E)  a supernova in the Large Magellanic cloud

Question 15

A planetary nebula is a(n) ____.

Accepted Answer

A)  expanding envelope of ionized gas expelled by a dying medium-mass star 
B)  expanding envelope of neutral gas and dust expelled by a dying medium-mass star 
C)  contracting envelope of dusty material from planets destroyed by a dying medium-mass star 
D)  contracting envelope of ionized interstellar medium absorbed by a dying medium-mass star 
E)  expanding atmosphere of a medium-mass star as it becomes a red giant 
A)  expanding envelope of ionized gas expelled by a dying medium-mass star 
B)  expanding envelope of neutral gas and dust expelled by a dying medium-mass star 
C)  contracting envelope of dusty material from planets destroyed by a dying medium-mass star 
D)  contracting envelope of ionized interstellar medium absorbed by a dying medium-mass star 
E)  expanding atmosphere of a medium-mass star as it becomes a red giant

Question 16

The process and result of a star's evolution off of the main sequence are determined primarily by the star's mass.

Accepted Answer

A) True 
 B)False

Question 17

The collapse of the iron core of an isolated massive star produces a type II supernova.

Accepted Answer

A) True 
 B)False

Question 18

The main observable difference separating Type I and Type II supernovae is ____.

Accepted Answer

A)  neutrino emission 
B)  iron absorption lines 
C)  a difference in luminosity of several thousand times 
D)  the presence or absence of hydrogen absorption lines 
E)  the presence or absence of hydrogen emission lines 
A)  neutrino emission 
B)  iron absorption lines 
C)  a difference in luminosity of several thousand times 
D)  the presence or absence of hydrogen absorption lines 
E)  the presence or absence of hydrogen emission lines

Question 19

A white dwarf generates energy through ____.

Accepted Answer

A)  gravitational contraction 
B)  hydrogen fusion 
C)  helium fusion 
D)  mass loss 
E)  rapid rotation 
A)  gravitational contraction 
B)  hydrogen fusion 
C)  helium fusion 
D)  mass loss 
E)  rapid rotation

Question 20

What part of the Sun's aging process will destroy Earth itself?

Accepted Answer

A)  the fusion of hydrogen in the core 
B)  an increase in luminosity as the core becomes helium-enriched 
C)  the expansion of the outer layers of the Sun as a red giant 
D)  the supernova explosion caused by the collapse of the iron core 
E)  hydrogen detonation on the white dwarf remnant 
A)  the fusion of hydrogen in the core 
B)  an increase in luminosity as the core becomes helium-enriched 
C)  the expansion of the outer layers of the Sun as a red giant 
D)  the supernova explosion caused by the collapse of the iron core 
E)  hydrogen detonation on the white dwarf remnant

Exam 13: Deaths of Stars

Stars larger than about 1.4 solar masses must lose mass in order to become white dwarfs.

Red dwarf stars ____.

White dwarfs are rare objects.

A medium-mass star evolves into a red giant because ____.

The gravitational field around close binary stars is defined by _______________ lobes.

What keeps red dwarfs from becoming giant stars?

A white dwarf stops collapsing and forms a stable structure due to forces arising from ____.

Almost all stars are in binary systems.

A normal white dwarf is approximately the same size as ____.

All stars ignite helium fusion as part of the aging process.

What is a planetary nebula?

Red dwarf stars (stars between 0.08 and 0.5 solar masses) evolve very differently than other stars as they age because ____.

Supernovae can trigger star formation.

The Crab Nebula is the remnant of ____.

A planetary nebula is a(n) ____.

The process and result of a star's evolution off of the main sequence are determined primarily by the star's mass.

The collapse of the iron core of an isolated massive star produces a type II supernova.

The main observable difference separating Type I and Type II supernovae is ____.

A white dwarf generates energy through ____.

What part of the Sun's aging process will destroy Earth itself?

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